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author | Marek Polacek <polacek@redhat.com> | 2021-03-04 20:20:40 -0500 |
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committer | Marek Polacek <polacek@redhat.com> | 2021-03-25 14:46:29 -0400 |
commit | 9efd72d28956eb79c7fca38e3c959733a3bb25bb (patch) | |
tree | 9b0f68d043434302324aec5adc59913ada762393 /gcc/cp/call.c | |
parent | 15d649f79d6b6dc336f6a32eec242b652a262a82 (diff) | |
download | gcc-9efd72d28956eb79c7fca38e3c959733a3bb25bb.zip gcc-9efd72d28956eb79c7fca38e3c959733a3bb25bb.tar.gz gcc-9efd72d28956eb79c7fca38e3c959733a3bb25bb.tar.bz2 |
c++: -Wconversion vs value-dependent expressions [PR99331]
This PR complains that we issue a -Wconversion warning in
template <int N> struct X {};
template <class T> X<sizeof(T)> foo();
saying "conversion from 'long unsigned int' to 'int' may change value".
While it's not technically wrong, I suspect -Wconversion warnings aren't
all that useful for value-dependent expressions. So this patch disables
them. This is a regression that started with r241425:
@@ -7278,7 +7306,7 @@ convert_template_argument (tree parm,
val = error_mark_node;
}
}
- else if (!dependent_template_arg_p (orig_arg)
+ else if (!type_dependent_expression_p (orig_arg)
&& !uses_template_parms (t))
/* We used to call digest_init here. However, digest_init
will report errors, which we don't want when complain
Here orig_arg is SIZEOF_EXPR<T>; dependent_template_arg_p (orig_arg) was
true, but type_dependent_expression_p (orig_arg) is false so we warn in
convert_nontype_argument.
gcc/cp/ChangeLog:
PR c++/99331
* call.c (build_converted_constant_expr_internal): Don't emit
-Wconversion warnings.
gcc/testsuite/ChangeLog:
PR c++/99331
* g++.dg/warn/Wconversion5.C: New test.
Diffstat (limited to 'gcc/cp/call.c')
-rw-r--r-- | gcc/cp/call.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/gcc/cp/call.c b/gcc/cp/call.c index bab0c89..e757e18 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -4484,6 +4484,9 @@ build_converted_constant_expr_internal (tree type, tree expr, && processing_template_decl) conv = next_conversion (conv); + /* Issuing conversion warnings for value-dependent expressions is + likely too noisy. */ + warning_sentinel w (warn_conversion); conv->check_narrowing = true; conv->check_narrowing_const_only = true; expr = convert_like (conv, expr, complain); |